I can do Japan and Japanese and most if not all of the Japanese origin or language fandoms nominated (it'd be easier to ask on a case-by-case basis than me listing all of them at this point, I think). I've researched just about every period of Japanese society at at least a shallow level, with a particular focus on modern/contemporary and ancient Japan. I'm not the person to ask about Buddhism in Japan except for how it relates to the moden period and the Asia-Pacific Wars, though I can do Shinto and Christianity.